commit a2e9d3f38ef8770ee7d2407055dfb60b83112a5c
parent b65b98b0476133970c7bc70285c076776b8f5c62
Author: Jack Mordaunt <jackmordaunt.dev@gmail.com>
Date: Sun, 20 Sep 2026 07:43:00 -0300
ntfs: put extra names at a fixed slot so a replay repeats itself
Extra names claimed the next free slot, so replaying a projection appended a
second node for every hard link unless the caller emptied the tree first. That
requirement is what forced the builder to zero the node count mid-scan, in full
view of a thread resolving paths from it.
Sizing for records and links together, and seating each link at its ordinal above
the record range, makes a repeated projection write the same slots as the pass
before it. Nothing has to be emptied, and the claim goes with it.
Diffstat:
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/ntfs/tree.odin b/ntfs/tree.odin
@@ -66,7 +66,10 @@ and names are borrowed from the table's arenas rather than copied, so repeating
allocates nothing. The table must therefore outlive the tree.
*/
to_tree :: proc(m: ^Mft, t: ^scan.Tree, p: ^Projection) -> scan.Error {
- if err := scan.reserve(t, u32(len(m.entries))); err != nil {
+ // Records take slot per slot, extra names the range directly above them. Sizing
+ // for both up front is what lets a replay land on the same slots as the pass
+ // before it, so repeating one never has to empty the tree first.
+ if err := scan.reserve(t, u32(len(m.entries) + len(m.links))); err != nil {
return err
}
if p.settled == nil {
@@ -80,7 +83,6 @@ to_tree :: proc(m: ^Mft, t: ^scan.Tree, p: ^Projection) -> scan.Error {
}
clear(&p.fresh)
- w := scan.writer(t, 0)
used, bytes: u64
for i in 0 ..< u32(len(m.entries)) {
@@ -120,14 +122,12 @@ to_tree :: proc(m: ^Mft, t: ^scan.Tree, p: ^Projection) -> scan.Error {
}
// Extra names for a file already counted. They belong in the tree so a file can
- // be found at every path it has, but their bytes must not be counted twice. Only
- // the ones not done before, or repeating this would add a node per link each
- // time. Links are merged when the scan ends, so this is empty until then.
- for l in m.links[p.links_done:] {
- index, err := scan.claim(&w, 1)
- if err != nil {
- return err
- }
+ // be found at every path it has, but their bytes must not be counted twice. Each
+ // sits at its ordinal above the record range, so a link written twice is written
+ // to the same slot. Links are merged when the scan ends, so this is empty
+ // until then.
+ for l, k in m.links[p.links_done:] {
+ index := u32(len(m.entries) + p.links_done + k)
n := scan.node(t, index)
n.parent = l.parent
n.name = l.name
